5 The Lord our God then reveals it, and by His Scriptures puts us in mind how it may be understood when judgment is spoken of. I exhort you, therefore, to give attention. Sometimes judgment means punishment, sometimes it means discrimination. According to that mode of speech in which judgment means discrimination, “we must all appear before the judgment-seat of Christ that” a man “may there receive what things he has done in the body, whether it be good or ill.” For this same is a discrimination, to distribute good things to the good, evil things to the evil.
For if judgment were always to be taken in a bad sense, the psalm would not say, “Judge me, O God.” Perhaps some one is surprised when he hears one say, “Judge me, O God.” For man is wont to say, “Forgive me, O God;” “Spare me, O God.” Who is it that says, “Judge me, O God”? Sometimes in the psalm this very verse even is placed in the pause, to be given out by the reader and responded by the people. Does it not perhaps strike some man's heart so much that he is afraid to sing and to say to God, “Judge me, O God”?
And yet the people sing it with confidence, and do not imagine that they wish an evil thing in that which they have learned from the divine word; even if they do not well understand it, they believe that what they sing is something good. And yet even the psalm itself has not left a man without an insight into the meaning of it. For, going on, it shows in the words that follow what kind of judgment it spoke of; that it is not one of condemnation, but of discrimination. For says it, “Judge me, O God.”
What means “Judge me, O God, and discern my cause from an unholy nation”? According to this judgment of discerning, then, “we must all appear before the judgment-seat of Christ.” But again, according to the judgment of condemnation, “Whoso hears my words,” says He, “and believes Him that sent me, has eternal life, and shall not come into judgment, but makes a passage from death to life.” What is “shall not come into judgment?” Shall not come into condemnation. Let us prove from the Scriptures that judgment is put where punishment is understood; although also in this very passage, a little further on, you will hear the same term judgment put for nothing else than for condemnation and punishment.
Yet the apostle says in a certain place, writing to those who abused the body, what the faithful among you know; and because they abused it, they were chastised by the scourge of the Lord. For he says to them, “Many among you are weak and sickly, and deeply sleep.” For many therefore even died. And he went on: “For if we judged ourselves, we should not be judged by the Lord;” that is, if we reproved ourselves, we should not be reproved by the Lord. “But when we are judged, we are chastened by the Lord, that we may not be condemned with the world.” There are therefore those who are judged here according to punishment, that they may be spared there; there are those who are spared here, that they may be the more abundantly tormented there; and there are those to whom the very punishments are meted out without the scourge of punishment, if they be not corrected by the scourge of God; that, since here they have despised the Father that scourges, they may there feel the Judge that punishes.
Therefore there is a judgment into which God, that is, the Son of God, will in the end send the devil and his angels, and all the unbelieving and ungodly with him. To this judgment, he who, now believing, passes from death unto life, shall not come.
Source: Tractates on the Gospel of John (New Advent)